Cannabis is a plant in the genus Cannabis that produces compounds called cannabinoids and terpenes. The two most well-known cannabinoids are THC (which is primarily responsible for psychoactive effects) and CBD (which is non-intoxicating). Cannabis has been used by humans for thousands of years for fiber, food, medicine, and ritual purposes.

Both hemp and marijuana come from the cannabis plant. In the United States, hemp is legally defined as cannabis containing 0.3% or less THC by dry weight. Marijuana generally refers to cannabis varieties with higher THC content. Hemp is used for fiber, seeds, and CBD products, while marijuana is typically associated with higher-THC cannabis used for its psychoactive effects.

Cannabinoids are chemical compounds that interact with the body’s endocannabinoid system. The cannabis plant produces phytocannabinoids (such as THC and CBD). The human body also produces its own endocannabinoids. Synthetic cannabinoids are lab-made versions that can mimic some effects of natural cannabinoids.

Terpenes are aromatic compounds found in cannabis and many other plants. They contribute to the smell and flavor of cannabis and may influence its effects. Common terpenes include myrcene, limonene, pinene, linalool, and caryophyllene.

Fatal overdose from cannabis toxicity alone is extremely rare. However, consuming very high doses — particularly from edibles — can cause significant discomfort, anxiety, rapid heart rate, nausea, paranoia, or in some cases, medical emergencies. This risk is higher for children, inexperienced users, and when large amounts are consumed at once.

Detection times vary depending on the type of test, frequency of use, metabolism, body fat, and the specific cannabinoid being tested. THC metabolites can be detectable in urine for several days to over a month in regular users. Blood and saliva tests generally have shorter detection windows.

Approximately 3 in 10 people who use cannabis develop cannabis use disorder, according to data from the Centers for Disease Control and Prevention (CDC). The risk is higher for those who begin use before age 18 and for people who use cannabis frequently or in high amounts. Cannabis use disorder can involve dependence and withdrawal symptoms when stopping use.

Current evidence does not show a clear causal link between cannabis smoking and lung cancer in most studies, unlike tobacco. However, smoking any plant material can irritate the lungs and respiratory system. Vaporizing or using non-inhalation methods may reduce this risk. More research is still needed on long-term respiratory effects.

Cannabis can affect mental health in complex ways. Some people use it to manage anxiety or sleep, while others may experience increased anxiety, paranoia, or other negative effects, especially with high-THC products. Regular use, particularly starting in adolescence, has been associated in some studies with increased risk of certain mental health issues. Individual responses vary significantly.

Yes. Cannabis can impair coordination, reaction time, attention, and decision-making, which can affect driving ability. Impairment is generally highest in the first few hours after use. All states prohibit driving while impaired by cannabis, though enforcement methods and legal limits vary by state.

There is conclusive or substantial evidence that cannabis or cannabinoids can help with certain types of chronic pain, chemotherapy-induced nausea and vomiting, and patient-reported spasticity in multiple sclerosis. Evidence for many other conditions is more limited or still developing. Results can vary significantly between individuals.

Current evidence does not support cannabis as a cure for any disease. It is primarily studied and used for symptom management and improving quality of life in certain conditions.

Medical cannabis is typically used with therapeutic intent under medical guidance, often with more attention to specific cannabinoid ratios, dosing, and product selection. Recreational use is generally driven by desired psychoactive effects. In some states, the same products may be available through both channels, though medical programs sometimes offer different tax rates or patient protections.

Major health organizations, including the CDC and the American College of Obstetricians and Gynecologists (ACOG), recommend avoiding cannabis during pregnancy and breastfeeding due to potential risks to fetal and infant development. THC can pass through the placenta and into breast milk.

Cannabis remains a Schedule I controlled substance under federal law. In April 2026, certain categories of medical cannabis products were moved to Schedule III, and a broader rescheduling process is ongoing. Most cannabis activity is still illegal under federal law.

Transporting cannabis across state lines generally violates federal law, even if both states have legalized it under their own laws. Air travel with cannabis is also prohibited under federal regulations.

No. A state-issued medical cannabis card provides protections under state law but does not protect against federal prosecution or enforcement actions.

Yes. Many employers maintain drug-free workplace policies regardless of state legalization. Certain industries, safety-sensitive positions, and federal contractors may have additional testing requirements. State legalization does not necessarily protect employees from workplace consequences.

As of July 2026, the SAFE Banking Act has not been enacted into law. Cannabis businesses continue to face challenges accessing traditional banking and financial services in many cases.

No consumption method is entirely risk-free. Many people consider lower-potency, precisely dosed products and non-inhalation methods (such as tinctures or capsules) to carry lower respiratory risks. Individual circumstances, tolerance, and health conditions vary significantly. Starting with low doses and going slow is generally recommended, especially for new users.

Consider your goals (e.g., relaxation, focus, pain relief, sleep), tolerance level, preferred method of consumption, and product testing information. Look for products from licensed sources with clear lab results (Certificate of Analysis) showing cannabinoid content and testing for contaminants. Starting with low doses is generally advisable.

Important information includes total cannabinoid content (especially THC and CBD), serving size, terpene profile (when available), lab testing results for potency and contaminants, ingredients, and expiration date. Products from licensed retailers are more likely to have undergone required testing.

Beginners are generally advised to start with a very low dose (“start low, go slow”), preferably in a safe and comfortable environment. It is helpful to keep track of how different products and doses affect you. Consulting a healthcare provider is recommended if you have medical conditions or take other medications.

Yes. Cannabis can interact with certain medications, including some blood thinners, sedatives, and drugs metabolized by the liver. It is important to discuss cannabis use with a healthcare provider or pharmacist if you are taking other medications.